JPH04229760A - Picture reader - Google Patents

Abstract

PURPOSE:To improve the quality of a read picture by eliminating an undesired flare light from an original or the like on an original read glass (contact glass). CONSTITUTION:The reader consists of a lighting light source 12, a lens array 16 in which plural lenses are formed continuously, a roof mirror array 18 in which plural roof reflection faces are formed continuously at an arrangement pitch of the lens array, an aperture plate 17 having a structure shielding a stray light between adjacent lenses arranged between the lens array and the roof mirror array, an optical path separation mirror 15, an image forming element comprising a housing 11 or the like, a nonmagnification sensor 19 and an original read glass 13 or the like. The light shield layer 14 is formed to a part on the surface of the original read glass other than the original read position which shields a flare light.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading device, and more particularly, to a 1-magnification contact image sensor used in a reading section of a facsimile, an image scanner, or the like.

0002

2. Description of the Related Art FIG. 10 is a diagram for explaining an example of a conventional image reading device using a convergent lens array.
3 is a fluorescent tube, 24 is a condensing lens, 25 is a converging light lens array, 26 is an original, 27 is an illumination width, 28 is a document surface glass, and the light emitted from the fluorescent tube 23 is passed through the condensing lens 24. The light is focused and illuminates the document surface 26. The length (illumination width) 27 of the illuminated portion on the document surface in the sub-scanning direction is determined by the light source 2.
The width is limited to 30 mm or less, preferably 2 mm or less, by the slit formed by the slit plates 22, 22 arranged between 3 (condensing lens 24 in the figure) and the original 26. The light reflected from the document surface is passed through the convergent optical lens array 2.
5, the image is formed on the same-magnification image sensor 21. According to the above-described configuration, it is possible to almost eliminate the blocking of light that is diffusely reflected on the portions of the document surface that are not involved in reading or on the document surface glass 28 and that enters the converging light lens array 25.

FIG. 11 is a diagram for explaining an example of the configuration of an image reading device using an RMLA (roof mirror lens array). array (LA) 32, roof mirror array (RMA) 33, LA32 and RMA
a diaphragm plate (not shown) disposed between 33 and
It is comprised of a housing member (not shown) for holding the components and blocking external light. The light from the object 34 is reflected by the SM 31, then transmitted through the LA 32, and then transmitted through the RMA.
It is reflected twice in total on each of the left and right surfaces of 33, and again, LA
After being transmitted through the same lens 32 and reflected again by the SM 31, it is imaged as an image 35 at a position conjugate with the object plane. An erect real image is formed in both the arrangement direction (Y direction) and orthogonal direction (X direction) of the LA 32 and RMA 33. In particular, since an erect, same-size image is formed in the Y direction, the necessary width is covered by overlapping images obtained by single LA and RMA in the Y direction. Since the arrangement pitches of the LA, aperture plate, and RMA are almost the same, the light amount distribution of each lens is almost the same. The light amount distribution of each lens is appropriately determined so that the light amount distribution in the Y direction is made uniform. In the conventional technique shown in FIG. 10, a slit is provided between the light source and the document, but there is no structure to prevent direct light from the light source from entering the imaging optical system. Therefore, it has drawbacks such as not being able to sufficiently prevent performance deterioration. In addition, in the conventional technique shown in FIG. 11, direct light from the illumination light source enters the transparent part of the optical path splitting mirror, is scattered inside the RMLA optical system, becomes flare light, and deteriorates imaging performance. It has the following disadvantages.

[0004] Furthermore, in the above-mentioned prior art, a slit is provided between the light source and the document, but the provision of the slit has drawbacks such as an increase in the number of parts and a time-consuming positioning adjustment.

[0005]

[Purpose] The present invention has been made in view of the above-mentioned circumstances, and is particularly aimed at a document reading glass (contact glass) of a 1-size image reading device, which removes unnecessary flare light from a document, etc., and reads the document. This was done for the purpose of improving the image quality, and furthermore, by forming the light shielding layer integrally with the contact glass, it was possible to improve positioning accuracy and reduce costs.

[0006]

[Structure] In order to achieve the above objects, the present invention provides (1)
an illumination light source, a lens array (LA) in which a plurality of lenses are continuously formed, a roof mirror array (RMA) in which a plurality of roof-shaped reflective surfaces are continuously formed at the arrangement pitch of the lens array; An imaging element consisting of an aperture plate disposed between a lens array (LA) and a roof mirror array (RMA) and configured to block stray light between adjacent lenses, an optical path separation mirror, a housing, etc. , in an image reading device comprising a same-magnification sensor, a document reading glass, etc., a light shielding layer is formed on a portion of the surface of the document reading glass other than the document reading position; or (2) an illumination light source. a lens array (LA) in which a plurality of lenses are continuously formed; a roof mirror array (RMA) in which a plurality of roof-shaped reflective surfaces are continuously formed at the arrangement pitch of the lens array; Array (LA)
and the roof mirror array (RMA), an imaging element (roof mirror lens array: RMLA) consisting of an aperture plate structured to block stray light between adjacent lenses, an optical path separation mirror, a housing, etc. , an image reading device comprising a same-magnification sensor, a document reading glass, etc., including a light shielding member structured to prevent direct light from the illumination light source from entering the inside of the RMLA optical system; , (3) An illumination light source, a lens array (LA) in which a plurality of lenses are continuously formed, and a roof mirror array (LA) in which a plurality of roof-shaped reflective surfaces are continuously formed at the arrangement pitch of the lens array. RMA), an aperture plate having a structure to block stray light between adjacent lenses between the lens array (LA) and the roof mirror array (RMA), an optical path separation mirror, a housing, etc. Child(
In an image reading device that includes a roof mirror lens array (RMLA), a same-magnification sensor, a document reading glass, etc., direct light from the illumination light source is transmitted to the RML.
A: A light shielding member structured to prevent light from entering the optical system, and a light absorbing member formed on the surface of the light shielding member, or (4) an illumination light source and a plurality of lenses connected in succession. The formed lens array (LA), the roof mirror array (RMA) in which a plurality of roof-shaped reflective surfaces are successively formed at the arrangement pitch of the lens array, and the lens array (LA).
An imaging element (roof mirror lens array: RMLA) consisting of an aperture plate structured to block stray light between adjacent lenses, an optical path separating mirror, a housing, etc. between the LA) and the roof mirror array (RMA); , in an image reading device comprising a same-magnification sensor and a document reading glass, a light shielding member is disposed on the back side of the reflective surface of the optical path separation mirror of the roof mirror lens array (RMLA), or (5) An illumination light source, a lens array (LA) in which a plurality of lenses are continuously formed, and a roof mirror array (RMA) in which a plurality of roof-shaped reflective surfaces are continuously formed at the arrangement pitch of the lens array. ), an aperture plate structured to block stray light between adjacent lenses between the lens array (LA) and the roof mirror array (RMA), an optical path separation mirror, a housing, etc. In an image reading device comprising a mirror lens array (RMLA), a same-magnification sensor, and a document reading glass, the optical path separating device is installed on the back side of the reflective surface of the optical path separating mirror of the roof mirror lens array (RMLA). A light shielding member having an L-shaped light absorption layer formed in close contact with the optical path separating mirror is disposed between the mirror and the contact glass. Hereinafter, the present invention will be explained based on examples.

FIG. 1 is a diagram for explaining an example of an image reading device configured using the rod lens array as described above. In the figure, 1 indicates a housing (frame) in which the rod lens array is housed; 2 is an LED light source, 3 is a contact glass, 4 is a light shielding layer, 5 is an equal-magnification imaging element (rod lens array), and 6 is an equal-magnification sensor. On the side facing the double imaging element 5, a light shielding layer 4 is integrally formed in a portion other than the width necessary for reading the original, and the light shielding layer 4 is formed integrally with the area other than the width necessary for reading the original. The system is designed to remove light other than the The light-shielding layer 4 can be formed by printing, painting, vacuum deposition, or other methods using a light-absorbing material on the surface of the contact glass. Alternatively, the absorbing layer may be formed after the contact glass is roughened (ground glass-like) at the position where the light-shielding layer is to be formed. In addition, in order to reduce costs, the LED illumination light source 2 has changed from the conventional one with a bar lens to one with a structure in which chip-type LEDs are arranged on a substrate. (GaAsP, GaAlAs
The entire plastic body covering the diodes (such as diodes) emits light (similar to a surface emitting light source) and is also the cause of flare light.

FIG. 2 is a configuration diagram for explaining another example. In the figure, parts having the same functions as those in the embodiment shown in FIG. 1 are designated by the same reference numerals as in FIG. It has been done. In this example, a light-shielding layer 4 is formed on the side of the contact glass 3 facing the original, and by providing the light-shielding layer on the original side, more unnecessary light is removed from the original surface than in the example shown in FIG. It is possible to remove flare light. Note that the light shielding layer 4 is shown in FIG.
The material may be the same as the example shown in , but chromium oxide, metal oxides such as chromium, metals, etc. may be formed on the glass surface by sputtering, vacuum deposition, or other methods. Furthermore, an antireflection film may be formed on the light source side surface of the contact glass by vacuum deposition, sputtering, or the like. Although not shown, it is easy to understand that the light shielding layer 4 may be provided on both sides of the contact glass 3 by combining the example shown in FIG. 1 and the example shown in FIG.

FIG. 3 is a diagram showing an embodiment of the present invention when a roof mirror lens array (RMLA) is used as an imaging element. In the figure, 11 is a housing (frame), 12 is an LED light source, and 13 is a contact. 14 is a light shielding member, 15 is an optical path separation mirror (SM), 16 is a lens array (LA), 17 is a diaphragm plate, and 18 is a roof mirror array (
RMA), 19 is a same-magnification sensor, and by using RMLA, it is possible to make it more compact than the conventional one using a rod lens array. Furthermore, by providing the light shielding layer 14 on the contact glass 13 as in the embodiment described above, light other than original reading light can be removed. In the case of RMLA, the object-side and image-side lights are separated via an optical path separation mirror 15, but they are used off the optical axis rather than on the optical axis, and are incorporated into the optical system. If the light beam is oriented on the contact glass with its axis parallel to the optical axis of the lens, it will have an asymmetrical shape.

That is, in FIG. 4, 12 is an LED light source, 13 is a contact glass, and 16 is a lens array. If the light flux taken into the optical system has an axis L1 parallel to the lens optical axis L0, The structure is asymmetrical as shown in FIG. 1, and therefore the light from the LED light source 12 is reflected by the contact glass 13 in the directions E and E', making it less susceptible to specularly reflected light from the contact glass. .

FIG. 5 is a diagram showing another embodiment in which the RMLA shown in FIG. The equal-magnification sensors 19 can be arranged substantially in parallel, the length (thickness) in the vertical direction of the figure can be reduced, and the device can be made more compact.

FIG. 6 shows the optical path separating mirror 15 and the illumination light source 1.
A plate-shaped light shielding member 141 is provided between the illumination light source 12 and the light source 12, so that the direct light from the illumination light source 12 enters the transparent part of the optical path splitting mirror 15, is scattered inside the RMLA optical system 18, becomes flare light, and is condensed. This is to prevent deterioration of image performance. In particular, in the transparent part of the optical path separation mirror 15,
Direct light from the illumination light source 12 is refracted on the surface of the transparent part (glass, plastic, etc.) of the light separation mirror 15 toward the lens array (LA) 16, and is then taken into the roof mirror lens array (RMLA) optical system. This is very effective. Furthermore, as in the embodiment shown in FIG. 3, a light shielding layer is integrally formed on the contact glass 13 side in a portion other than the width necessary for reading the original, so that the reflected light from the optical path separation mirror side of the contact glass (original It is also possible to add a configuration that removes light outside the reading position) and direct light from the LED illumination light source.

FIG. 7 is a block diagram for explaining another embodiment of the present invention. In the embodiment shown in FIG. This is characterized in that a plate-shaped light shielding member 141 having a member 14a is provided. The light absorption layer 14a is a light shielding plate 141
A light-absorbing material can be formed on the surface by printing, painting, vacuum deposition, or other methods. Alternatively, the light absorbing layer may be formed after forming a rough surface (frosted glass) at the position where the light shielding layer is to be formed. Furthermore, a method of chemically etching the metal surface of the aluminum alloy with acid, alkali, etc. to make it rough, and then forming a black Al2O3 film (anodized film);
Various methods can be used, such as depositing a black absorption layer on the surface of the Cu alloy. Note that if an illumination light source in which chip-shaped LEDs are arranged linearly on a substrate is used as a light source for the configuration of the embodiment shown in FIGS. 6 and 7, less flare light will be generated and assembly adjustment will be easy. , are effective because of their low cost, but it is also possible to use fluorescent tubes, cold cathode fluorescent tubes, LEDs with bar lenses, halogen lamps, and the like.

FIG. 8 is a diagram for explaining another embodiment of the present invention. In this embodiment, a plate-shaped plate is provided closely to the optical path separating mirror 15 between the optical path separating mirror 15 and the illumination light source 12. A light shielding member 142 is provided to remove reflected light from the optical path separation mirror side of the contact glass 13 (light other than the original reading position) and direct light from the LED illumination light source.

FIG. 9 is a configuration diagram for explaining still another embodiment of the present invention.
A light shielding member 143 having a light absorption layer formed thereon and having an L-shaped tip and bent toward the contact glass 13 is disposed in close contact with the optical path separation mirror 15 between the LED illumination light source 12 and the contact glass 13. reflected light from the optical path separation mirror 15 side (light other than the original reading position) and the LED
Direct light from the illumination light source 12 is removed. Note that by forming the L-shape, it is possible to effectively block light other than the imaging effective light flux, and also effectively remove diffuse reflected light generated when light from the LED illumination light source is reflected on the surface of the light blocking member. I can do it.

[0016]

[Effect] As is clear from the above description, according to the invention as claimed in claim 1, by integrally forming the light shielding layer on the contact glass, light other than the effective imaging light from the light source is effectively removed. becomes possible. Furthermore, by integrally forming it, there is no need to provide slits and adjust the position as in the conventional case, making manufacturing (assembly) easier. Furthermore, in addition to the above effects, by using RMLA, it becomes possible to more effectively remove light other than effective imaging light. According to the second aspect of the invention, it is possible to prevent direct light from the illumination light source from entering the transparent portion of the optical path splitting mirror, scattering and becoming flare light inside the RMLA optical system, and deteriorating the imaging performance. In particular, direct light from an illumination light source enters the transparent portion of the optical path splitting mirror, is refracted toward the lens array (LA) side by the surface of the transparent portion (glass, plastic, etc.) of the optical path splitting mirror, and is refracted toward the roof mirror lens array. (
RMLA) It is highly effective because it can remove and reduce the flare light that is generated and captured inside the optical system. Furthermore, flare light that is reflected by the surface of the contact glass on the lens array (LA) side and enters the interior of the roof mirror lens array (RMLA) optical system can also be removed at the same time. Claim 3
According to the invention described in , by forming a light absorption layer on the surface of the light shielding member, flare light reflected and scattered on the surface of the light shielding member can be more effectively removed and reduced. According to the invention set forth in claim 4, flare light generated by reflection on the surface of the optical path splitting mirror can be effectively removed and reduced, and the light shielding member can be disposed closer to the contact glass, so that it is possible to reduce the flare light from the LED light source. Light other than the effective illumination light can be more effectively removed and reduced. According to the invention set forth in claim 5, in addition to the effect set forth in claim 5, by forming the light shielding member into an L shape, light other than the effective light beam for imaging is effectively blocked, and light from the LED illumination light source is At the same time, it is possible to remove diffusely reflected light generated when the light is reflected on the surface of the light shielding member.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram for explaining an example of a case where a convergent lens array is applied to an image reading device.

FIG. 2 is a configuration diagram for explaining another example in which a convergent lens array is applied to an image reading device.

[
FIG. 3 is a configuration diagram for explaining an embodiment of the present invention when RMLA is applied to an image reading device.

4 is a detailed view of the main parts of the embodiment shown in FIG. 3. FIG.

FIG. 5 is a diagram showing another example using RMLA.

FIG. 6 is a diagram showing still another embodiment using RMLA.

FIG. 7 is a diagram showing still another embodiment using RMLA.

FIG. 8 is a diagram showing still another embodiment using RMLA.

FIG. 9 is a diagram showing still another embodiment using RMLA.

FIG. 10 is a diagram showing an example of an image reading device using a conventional converging lens array.

FIG. 11 is a diagram showing an example of an image reading device using a conventional RMLA.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Housing, 2... LED light source, 3... Contact glass, 4... Light shielding layer, 5... Rod lens array, 6... Equal magnification sensor, 11... Housing, 12... LED light source, 13... Contact glass, 141, 142, 143 ...shading member,
15... Optical path separation mirror, 16... Lens array, 17... Aperture plate, 18... Roof mirror array, 19... Same-magnification sensor.

Claims (5)

[Claims] 1. An illumination light source, a lens array in which a plurality of lenses are continuously formed, a roof mirror array in which a plurality of roof-shaped reflective surfaces are continuously formed at the arrangement pitch of the lens array, and the lens. An aperture plate disposed between the array and the roof mirror array to block stray light between adjacent lenses, an optical path separating mirror, an imaging element composed of a housing, etc., a 1x sensor, and an original. An image reading device comprising a reading glass or the like, characterized in that a light shielding layer is formed on a surface of the document reading glass other than the document reading position. 2. An illumination light source, a lens array in which a plurality of lenses are continuously formed, and a roof mirror array in which a plurality of roof-shaped reflective surfaces are continuously formed at an arrangement pitch of the lens array; An aperture plate that blocks stray light between adjacent lenses between the lens array and the roof mirror array, an optical path separation mirror, an imaging element composed of a housing, etc., a 1-magnification sensor, a document reading glass, etc. An image reading device comprising: a light shielding member configured to prevent direct light from the illumination light source from entering the imaging element optical system. 3. An illumination light source, a lens array in which a plurality of lenses are continuously formed, and a roof mirror array in which a plurality of roof-shaped reflective surfaces are continuously formed at an arrangement pitch of the lens array; An aperture plate that blocks stray light between adjacent lenses between the lens array and the roof mirror array, an optical path separation mirror, an imaging element composed of a housing, etc., a 1x sensor, a document reading glass, etc. An image reading device comprising: a light-shielding member that prevents direct light from the illumination light source from entering the imaging element optical system; and a light-absorbing member is formed on the surface of the light-shielding member. An image reading device characterized by: 4. An illumination light source, a lens array in which a plurality of lenses are continuously formed, and a roof mirror array in which a plurality of roof-shaped reflective surfaces are continuously formed at the arrangement pitch of the lens array; an aperture plate that blocks stray light between adjacent lenses between the lens array and the roof mirror array;
In an image reading device consisting of an optical path separating mirror, an imaging element consisting of a housing, etc., a 1x sensor, a document reading glass, etc., the back side of the reflective surface of the optical path separating mirror of the roof mirror lens array. An image reading device characterized in that a light shielding member is provided. 5. An illumination light source, a lens array in which a plurality of lenses are continuously formed, and a roof mirror array in which a plurality of roof-shaped reflective surfaces are continuously formed at the arrangement pitch of the lens array; Between the lens array and the roof mirror array, there is an aperture plate structured to block stray light between adjacent lenses, an imaging element consisting of an optical path separation mirror, a housing, etc., a 1x sensor, a document reading glass, etc. In the image reading device, an L-shaped lens is provided on the back side of the reflective surface of the optical path separating mirror of the roof mirror lens array, between the optical path separating mirror and the contact glass, and in close contact with the optical path separating mirror. An image reading device characterized by disposing a light shielding member having a light absorption layer formed thereon.